Printing plate cylinder



Jan. 7, 1958 c. A.HARLE:ss

' PRINTING PLATE CYLINDER 3 Sheets-Sheet l Filed Feb. 11, 1953 N TWIN mxm,

Y JNVENTOR.

' CafesHf/rfess C A. HARLESS PRINTING PLATE CYLINDER Jan. 7,Y 1958 A5 Sheets-Sheet 2 Filed Feb. 1l, 1953 INVENTOR. Chf/s Z955 mams Jan. 7, 1958 Y c. A. HARLEss v 2,818,806

PRINTING PLATE CYLINDER Filed Feb. 1I. 195:15 s sheets-sheet s l fl y United States Patent ice PRlNTlNG PLATE CYLINDER Charles A. Harless, Riverside, Conn., assignor to R. Hoe & Co., inc., New York, N. Y., a corporation of New York Application February 11, 1953, Serial N0. 336,236

9 Claims. (Cl. 101-378) This invention relates to improvements in printing plate cylinders, and, more particularly, in the means for fixing stereotype or similar printing plates to the cylinders. The invention is particularly concerned with cylinders of the type in which the plates are held on `the cylinder by clamping arrangements engaging in recesses underneath the plates adjacent their straight edges.

it is an object of the invention to provide an improved plate clamping arrangement which permits a slight cocking of a plate relative to the cylinder.

A further object of the invention is to provide a spring clampin y mechanism, in which the parts are adjusted to the clamping position or unclamping position, and there is little or no tendency to move from such .position due to the clamping action or action of the springs.

A still further object of the invention is to provide an improved means for loosening or dislodging a plate to facilitate its removal.

With these and other objects which will appear in mind, a cylinder embodying the invention in a preferred form will now be described with reference to the accompanying drawing and the features forming the invention will then be pointed out in the appended claims.

In the drawing:

Figure l is a plan view of the cylinder;

Figure 2 is a partial plan view of the cylinder, showing the plate clamping assemblies in a different position;

Figure 3 is an end elevation of the cylinder;

Figure 4 is a plan view on an enlarged scale of part of the cylinder, showing a clamping mechanism unit with covering plate in place and another such unit with cover plate removed to show internal structure;

Figure 5 is a iioated view of part of the clamping unit of Figure 4, frame structure and other vparts `being removed to reveal the structure of the mechanism shown more clearly;

Figure 6 is an end elevational view of the parts shown in Figure 5;

Figure 7 is a View similar to Figure 6, but showing the parts in another operating position;

Figures 8, 9 and 10 are sectionsv on the respective lines rr- 8, 9--9 and 10-10 of Figure 4; and

Figure 1l is a section on the line 11--11 of Figure 8, with parts removed and showing `principally the mechanism for adjusting the plate clamping hooks vfor registering a plate.

The present. invention is an improvement upon that disclosed in prior Harless application Serial No. 296,940, tiled May 3l, 1952, for Printing. Plate Cylinder, now U. S. Patent No. 2,708,875, and is particularly concerned with the clamping assemblies.

The cylinder 1 carries a number of plates 2, kthe outlines of which are indicated in phantom in Figure l. As usual, the cylinder illustrated may carry a total of eight plates, arranged four across and two around the cylinder, andthe plates at'one end ofthe cylinderbeing staggered or angularly displaced with reference `to plates at Patented Jan. 7, 1958 2 the other end of the cylinder, for reducing vibration in printing. A number of plate clamp units 3 and spacer blocks 4 are provided, and the plate clamp units are operated in groups of four by means of shafts 5, the ends of which project out from the ends of the cylinder and are provided with a mechanism indicated generally at 6, for turning them from clamping to unclamping position, or vice versa. Y

The cylinder is provided with generally rectangular axial grooves or channels 7, having axial dovetail holding grooves S formed in their radially inward or bottom surfaces. Bores 9 (Figures 4, 8) communicatingwith the channels 7 to one side thereof, accommodate the operating shafts 5.

The operating mechanism comprises, for each shaft 5, an arm 10 fixed to the shaft, a link 11 pivotally connected to the end of the arm 10 and also pivotally connected to an arm 12 rotatably fixed to the .cylinder end. An extension 13 of the arm 12 has a socket 14 ttor taking a wrench 15.

In Figure 3, the operating mechanism associated with a shaft 5 is shown in full lines in clamping position, and in phantom in the unclamping or releasing position. Motion toward and away from plate clamping position is limited by a stud 16 against which van adjustable stop screw 17 abuts in the clamping position, and against which the extension 13 of arm 12 abuts in the unclamped position. Spring detents 18 and 19, of usual type,` engaging in a recess under the arm extension 13, serve to hold the operating mechanism in the clamped or unclarnped position, as desired.

The clamping assemblies 3 are adjustably fixed in the channel or groove 7, as later describedV in detail, vand may be rearranged as indicated in Figures 1 and 2 for taking plates of Iditerent widths, the spacer blocks 4 being relocated accordingly, as indicated in those figures, and generally as described in the above mentioned prior application.

Each clamping unit 3 (Figures 4 and 8 to 1l) comprises a block or frame structure composed of a lower member 26 and upper member 27 joined to it by means of bolts 28, so as to form a rigid structure for supporting the operating parts. In Figure 4, la clamping unit is shown with upper member 27 in place and another clamping unit with the upper member removed to show internal structure. The lower block 26 is cut to an are 30, completing the bore 9 which accommodates the operating shaft 5, and the two members 26 and 27 are recessed and cut away to accommodate the ,clamping mechanisms now to kbe described.

The clamping unit is held in the channel 7 by means of dovetail blocks 31, fitting in the dovetail groove 8. Bolts32 Vcountersunk in the upper block 27 -and having their threaded ends engaging in correspondingly threaded bores in the members 31 are utilized for securing the yclamping unit in position, by tightening up on the bolts 32, but permit adjustment of the clamping unit by loosening `the bolts 32. The spacer blocks 4 may, in some case, be provided with similar mechanisms for adjustably fas-tening them in the channel 7, as shown in the above mentioned application. An improved arrangement, which permits the use of narrower spacing 'blocks and also simplifies Athe construction is, however, preferred. In this arrangement, the spacer blocks 4 are formed with grooves 35, and the upper members 27 of the clamping unit blocks are formed with overhanging ledges 36 fitting in the grooves 35, so that the spacer blocks 4 are held in position by the clamping units 3. As will be apparent, it is possible to use a much smaller filler 4 than maybe used. with the liller block attachment of the above mentioned application. The undercutting of the blocks 4 does not, of course, interfere with the use of filler blocks y'held l 3 in place as in the above application, wherever this may be desired.

IIn a preferred arrangement, provision is made for re locating the clamping units without removing them, and for accurately registering them for holding plates of Various widths and printing from webs of various widths. The outer ends of the channels 7 are closed off by end blocks or caps 38 held to the cylinder by bolts, as indicated, and a retainer and register block 39 is used, being held in placel by a screw (not shown) cooperating with a dovetail block 31, fitting in the dovetail groove 8 for holding it adustably in position in the channel, as in the case of the clamping units 3.

As viewed in the axial direction, the member 39 is generally flush with the cylinder surface and with the upper surface of the clamping units 3. it is provided, however, with registering lugs 39', extending in a radial direction beyond the cylinder periphery generally, for a quarter of an inch or so, to permit registering the curved edge of the outside plate, under certain conditions. The block 39 is also cut out to accommodate shaft 5 on each side, so that it may be reversed in the channel 7, under certain conditions.

The cylinder of Figure 2 is shown as arranged for printing from a wide web, as, for example, a 68 inch web, producing four 17 inch page widths. In this case, the block 39 has been removed, and the curved edge of the outside plate may be registered against a pin (not shown) inserted in the end cap 3S or cylinder body 1, spacers 5 of suitable width being used to position the clamping units properly with relation to the recesses cut underneath the plates adjacent their straight edges.

In Figure 1, the parts are shown as arranged for printing a narrower web, as, for example, for printing four inch page widths from a 60 inch web, in which case, the outer curved edge of the end plate is registered against the lugs 39. For still smaller web and page widths, such as four 14 inch page widths, printed from a 5 6 inch web, -the blocks 39 may be reversed so as to bring the register lugs 39 ush against the end clamping unit 3, spacer blocks 4 of suitable width being used, as before.

The distance between block 39 and end cap 38 is sufficient to permit the insertion and removal of spacer blocks, by merely loosening up on the screws 32, so as to permit separating the clamping units 3 and removing and replacing the spacer blocks, which operation requires only the necessary space for clearing the spacer blocks 4 from under the ledges 36 of the clamping units 3. Where the parts are being arranged for the widest web, it is necessary in any event, only to remove the end cap 38 and slide the parts slightly from the end of the channel 7.

Each'clamping unit 3 includes a pair of hooks or clamps 40 for taking one straight edge of a plate and a pair of hooks 41 for taking a straight edge of another plate. Hooks 40 are substantially rigid to serve to locate the plate properly for register, while the hooks 41 are spring pressed so as to allow for any variation which may exist in the location of the recesses under the plate in which the hooks engage, thus insuring that `all hooks will be in firm engagement at all times.

Each hook 40 is formed at the end of one arm of a bell crank 43, pivotally carried on a short shaft 44 supported in the lower member 26 of the clamping unit frame or block. The other arms `45 of the bell crank receive trunnions 46 to each side of a block 47. The central part of the block 47 is formed with a concave spherical 'seat 48 and with a central bore 49.

A hook adjusting element Sil (Figures 8 and 1l) is provided and comprises a convex annular spherical surface 51 cooperating with the seat 48 and a shank 52 extending through the bore 49 with clearance on all sides and with its tip threadably engaged in an extension 53 of the lower block member 26. T he upper end of the adusting` member 50 is formed with means, such as a hexagonal socket 54 (Figure 4), to permit turning this member. Spring pressed plungers S5 (Figures 9 and 1l) seated in the extension 53 may also be provided for taking up slack between member 47 and the lower block extension 53. Turning member 50 in one direction will force the block 47 radially inwards, thus adusting the hooks 40 in the clamping direction (counterclockwise in the sectional views), while turning the member 50 in the other direction will adjust these hooks in the reverse direction. The trunnions on member 47 are rounded, as shown, and co operate with cylindrical bores in the ends of the bell crank arms 45, thus forming a self-aligning connection between the member 47 and each of the bell cranks. The positioning arrangement for the bell cranks accordingly forms la whifl'letree, so that by turning the member 50 the circumferential position of the pair of units may be determined as accurately as desired, while, at the same time, permitting one hook of a pair to be slightly in advance of this position and the other slightly in back of it. Where the plates are to be set straight on the cylinders, as is usual, this whiffletree arrangement permits the units to adjust for firmly gripping in both recesses in the plate, even though there may be a slight variation in the location of these recesses in the circumferential direction. Moreover two pairs of hooks 40 of two adjacent clamping units 3 which cooperate with the same straight edge of the same plate, may be displaced circumferentially from each other, permitting the attachment of the plate in a slightly skewed position wherever necessary. The whiletree mounting of the hooks of each pair will cause the four hooks of the two pairs to align themselves substantially along a very slight helix, so as to engage firmly under the plate at four points, while the plate is in a cocked or skewed position.

The hooks 41 are formed at the outer ends of members 60, pivotally mounted on a shaft 61 xedly carried in the lower block member 26, and held from rotation therein as by means of set screws 62. The central part of shaft 61 may be recessed or partly cut away, so as to provide clearance for the movement of other parts, while making the construction as compact as possible. The hook carrying member 60 is formed with a projecting finger or lug 63 received within a groove 64 in the shaft 5 (Figures 5, 6 and 8), and cooperating with one wall of this groove for withdrawing the member 60 to unclamping position, as indicated in Figures 7 and 9. The members 60 are further provided with bores 70 (Figures 5, 6 and 7) elongated in the circumferential direction about the axis of shaft 61, and receiving the ends of a shaft 71. The elongation of the bores or apertures 70 is such as to provide for a limited play or relative movement between the shaft 71 and the members 60 (ordinarily, about an eighth of an inch of play or so is suitable).

Shaft 71 carries poppet blocks 72, and a rotatable roller 73 for cooperating with the cam shaft 5. Poppet rods 74 formed with the blocks 72 are surrounded by a pair of compression springs 75. A cross bar or thrust block 76 slidably receives the ends of the poppet rods 74, and is provided with trunnions 78 to which are pivotally attached a pair of links 79. The other ends of links 79 are pivotally attached to the member 60 by pins 80 having threaded sections and heads for screwing into the members 60.

The shaft 5 is provided with a recess 81 for seating the roller 73 in the unclamped position, with a rise 82 for pushing the roller and clamping up the plate, and with a high dwell 83 for holding the roller in plate clamping position.

With the parts -in the position of Figures 7 and 9, in which the hooks 41 are not engaged in the plate, the springs are permitted to push the cross piece 76 and poppet blocks 72 as far apart as permitted by the play between the parts. In this position, the links 79 will be under tension (applied between members 60 and cross a.) bar v76), while .the springs 75 will force shaft 71 to Ithe limit 'of v:its movement in the Icircumferentia'lly elongated bore 70. It will be apparent -that in this position, the parts 72 and 76and the links 79 form a pre-loaded spring assembly which will move the members 60 or move with the members 60, as required, and without affecting the compression of springs 75 until the movement of the members 60 may be interfered with. Thus, the assembly just discussed moves bodily from the position of Figure toward that of Figure 4 when shaft 5 is rotated to clamp the plate, until a hook 41 engages the plate. At this point, any appreciable further movement of the hook 41 and of the member 60 on which it is formed is -prevented. Further rotation of the shaft 5 continues to move the yroller 73 and shaft 71 upon-which it is mounted, this movement being permitted by the elongation of the slot 70 in the members 60. However, block 76 is restrained from movement relative to the arms 6i) by the links 79 and will cease moving when the arms 60 are prevented from moving. Accordingly, the movement of roller 73 after the hooks 41 engage, moves blocks 72 slightly toward block 76. As soon as this happens, the full compression of springs 75 is applied through cross piece 76 and llink 79 to the hook supporting members 60. Movement of the roller`73 may continue for any desired distance up to the play between shaft 71 and the members 60. The springs 75 are preferably long in the physical sense, so that the spring pressure applied is substantially constant even though the actual compression of the spring .may vary within 4the limits Vof movement permitted.

In retreating the clamps from the position of Figs. 6 and '8, shaft 5 is rotated clockwise. The rst effect of this is` to permit the Aspring 75 to push the roller 73 .back until shaft 71 seats against one end of the bores 70 in the members l60. The spring assembly now becomes inert. The `further retraction to the position of FigureY 5 is accomplished by the wall of the groove 64 engaging the fingers ,63 Aon the members 60 and moving these members to the position of Figure 5.

,Provision is made for knocking loose the end of Va plate asit is unclamped. For this purpose, there is formed on a link `79 a projection 90. In the clamped pQSition this is located approximately midway between the two plates. However toward the latter part of the t retracting movement of the arm 60, -the projection 90 forces the edge of the plate circumferentially suciently so as to dislodge it from a cylinder and permit easy removal.

It will be understood that the clamping arrangements shown in Figures 4 and 5, when used with approximately semi-cylindrical plates as is usual, will be reduplicated on the opposite side of the cylinder and symmetrical with respect to the cylinder axis. Thus, each plate will be gripped on one straight edge by a pair of hooks 40 and on its other straight edge by a pair of hooks 41. Plate stop screws 91 may be provided where desired, the pressman resting an end of the plate against these screws preliminary to clamping it up. As is apparent, the plate detaching elements 9i) may be masked by these stop screws, so that the clamping mechanism is protected from accidental injury by the dropping of a plate.

It will be apparent that in the unclamped position, the parts are not under any stress, so that no force is required to hold the operating shafts 5 in position, the spring plungers or detents 19 being provided merely for convenience and to give the pressman a deinite indication that the mechanism is in the unclamped position. 'The high dwell 83 may be cylindrical and concentric with the cylindrical part of the shaft 5 generally, or may be slightly flattened, if desired. In any event, since the action of the roller 73 against the high dwell 83 is along a line through the axis -of the shaft 5, it merely tends to force this shaft against the cylindrical bore 9 in the cylinder, creating no tendency to -turn the shaft. It is thus lunnecessary to hold the shaft in the clamped position against any substantial '6 stress, so v'that the spring plunger or detent 19 serves merely .to-holdthe .parts against any slight tendency toward dislodgement which may exist due to vibration or other accidental causes.

It will be noted, that in the clamping position the recesses or grooves 64 and 81 of the shaft 5 are located on vthe same side as the clamping unit with respect to a plane through the axes of the cylinder and of the shaft 5. Any turning moment of shaft 5 due to centrifugal force will, therefore, be exerted in the clamping direction, or clockwise in the gures In this position, the link 11 and arm 12 are at dead center or in alignment, so that the shaft 5 is positively prevented from turning due to action of centrifugal force. Screw 17 in the operating arm 12 may be adjusted as necessary to maintain a straight alignment of the parts when the shaft is in clamping position. Arm extension 13 is positioned radially outward from the link 11 and arm 12 in the clamping position and is made sufciently massive so that centrifugal force on these parts also tends to press the screw 17 .against-the stop 16.

As Vbest shown in Figures 6-9 and 1l, the upper block member 27 is formed with .a iiat, chordwise surface 92, against which the block 76 and links 79 may slide, the motionon .this end ,of the spring assembly being otherwise free. lnthe clamping position of Figure 6, the compression yof springs 75 vacting against cross block 76 creates a Vslight counterclockwise moment about the pivots 80, holding the block up against the surface 92, and in the retracted position of Figure 7, this moment is somewhat increased. When the projection (Figure 9) engages a plate for dislodging it, a surface 93 formed on block 2.6 supports .the cross piece 76 when necessary.

What is Aclaimed is:

l. ln a printing cylinder, plate clamping mechanism comprising spring means for engaging under the substantiallyaligned straight edges of a pair of neighboring `plates and rigid clamping means for engaging under the opposite straight edges of the plates and holding the same against the action of the spring means, the rigid clamping means comprising a series of hooks including two neighboring sets of hooks, each set comprising two pairs of neighboring hooks for engaging in recesses under a said plate, means vfor holding the hooks in plate engaging position and comprising a separately adjustable member for holding each pair of hooks in plate engaging position, a diierential connection between the two hooks of each pair and its lsaid adjustable member, and means for individually and independently adjusting the position of each said adjustable member, whereby one of the said pairs of hooks may be displaced circumferentially from the other pair, and the four hooks of the two pairs will engage in aligned recesses under a slightly skewed plate.

2. In a printing cylinder, plate clamping mechanism comprising spring means for engaging under a straight edge of a plate and rigid clamping means for engaging rndcr the opposite straight edge of the plate and holding the same against the action of the spring means, the rigid clamping means comprising two pairs of hooks for engaging in recesses under the plate, a bar for each pair of hooks and connected at its ends to the hooks of the `said pair for holding them in plate engaging position, pivots supporting the said bars centrally, and adjustable means for moving said pivots to displace one of the said pairs of hooks circumferentially from the other pair, where by the bars will pivot to engage the four hooks of the two pairs in aligned recesses under a slightly skewed plate.

3. In a printing cylinder, plate clamping mechanism comprising a pair of hooks `engaging in recesses under a plate adjacent a straight edge thereof, means for mounting the hooks in the cylinder for movement about an axially extending pivotal axis, a bar, means connecting the bar to the hooks at its ends for pivoting them into and holding them in plate engaging position, a bar adjusting mem- '7 ber and a pivotal connection between.v the said member andthe bar, whereby the bar may be bodily adjusted to move the hooks circumferentially as a pair, but will pivot for engaging the hooks in plate vrecesses ut`of axial alignment with the cylinder.

4. ln a printing cylinder, plate clamping mechanism comprising a pair of bell cranks having hookarms for engaging in recesses underneath a plate for holding it on the cylinder, means pivotally mounting the bell cranks in the cylinder for pivoting movement about an axially extending axis, abar pivotally connected to the other arms of the said bell cranks, and means adjusting the position of the bar radially of the cylinder for adjusting the hooks circumterentially thereof, the last said means comprising an adjusting memberand apivotal connection between the same and the middleof the bar, whereby the bar may be bodily adjusted to move the hooks circumerentially as a pair, but will pivot for engaging the hooks in plate recesses out of axial alignment with the cylinder.

5. In a printing plate cylinder, plate clamping mechanism comprising a hook for engaging in a recess under a plate, means pivotally mounting the hook for movement between an extended plate clamping position and a Ietracted unclamping position, an operating member, and a preloaded spring assembly connecting the operating member and hook and comprising a thrust member, a lost motion connection between the operating member and the hook, the lost motion being a fraction of the total hook movement, a tension link pivotally connected to the hook and to the thrust member, and a spring compressed between the operating member and thrust member when the lost motion is taken up, and operable when the hook is held and the operating member is moved, for further compressing the spring and applying spring force to the hook through the tension link.

6. Plate clamping mechanism according to claim 5, comprising also means for guiding the thrust member in its movement following the hook when the hook is moved between clamping and unclamping position.

7. In a printing plate cylinder, plate clamping mechanisrn comprising a pair of hooks for engaging in recesses under a plate, means pivotally mounting the hooks for movement between an extended plate clamping position and a retracted unclamping position, an operating member, and a preloaded spring assembly connecting the op- 8 erating member and hooks lost motion connections between the operating member and the hooks, the lost motion being a fraction of the total hook movement, tension links pivotally connected to the hooks and to the cross block, and a spring compressed between the operating member and cross block when the lost motion is taken up, and operable when the hook is held and the operating member is moved, for further compressing the spring and applying spring force to the hooks through the tension links.

8. Plate clamping mechanism according to claim 7, comprising also means for guiding the cross block in its movement following the hooks when the hooks are moved between clamping and unclamping position.

9. A printing plate cylinder having an axially extending groove, clamping unit assemblies slidably fitting in the said groove, means for fastening the clamping unit assemblies in the groove to provide for plates of different Widths, spacer blocks between and abutting against the clamping unit assemblies, and means for detachably attaching the spacer blocks to the clamping unit assemblies for holding the .spacer blocks within the groove, the last said means comprising overhanging ledges formed on the clamping unit assemblies and cooperating grooves formed in the spacer blocks and receiving the said ledges.

References Cited in the le of this patent UNITED STATES PATENTS 1,343,220 Mast June 15, 1920 1,774,777 Wood Sept. 2, 1930 2,047,357v Crafts July 14, 1936 2,050,950 Huck Aug. 11, 1936 2,123,997 VJirousek July 19, 1938 2,195,491 Marchev Apr. 2, 1940 2,236,230 Q Worthington Mar. 25, 1941 2,248,612 Y Crafts July 8, 1941 2,428,263 Crafts et al. Sept. 30, 1947 2,474,127 Tollison et al June 21, 1949 2,496,200 Crafts Jan. 31, 1950 2,639,668 Chase et al. May 26, 1953 2,645,177 Dressel et al. July 14, 1953 2,694,976 Huck Nov. 23, 1954 2,708,875 Harless May 24, 1955 and comprising a cross block, 

